Just called this number. It is the American Institute for Cancer Research. During the recorded message, there is an option for you to chose regarding not receiving any future calls.
I too received a call from 2023679096. I called back to have my number removed from their call list. To achieve this you must press 1 which, per their message, is the option to receive more information about their program. I then followed the directions to remove my number from their call list. Let's hope it is successful.
If you get one of the modern phones, you can put in all the numbers that you don't want to call back. They just get a busy signal; you hear nothing. Get yourself a new, modern phone. It will be worth it all.